Dear SPM users,
I need to perform a second level statistic for fMRI but, in few words, I
don't know how.
My problem is:
6 subjects
2 session / subject (before and after therapy) which have the same
structure: A, B, Rest, A, B, Rest,.......with 5 scans/condition
180 scans/session
I need to compare the same condition on all the subjects between sessions,
one subject against another, one condition against the other and so on to
make all the possible comparisons.
For 4 subjects I could performe a fixed effect model and I had good
results; now, with 6 subject, I need a random effect model (for memory
problems) and I have some problems.
I have performed a fixed effect model for each subject so I have the
Con_*.img files corresponding to the effects of interest to introduce in a
second level statistic but, first of all, I don't know which is the best
model to analyze
6 subjects
2 session/subj
2 condition + baseline
1scan/condition
Can I also use PET model or not (for example considering the problem like:
2 groups, 6subj/group, 2cond+Rest, 1scan/cond)?
After the theoretical problem, there is the practical one:
I tried to specify some statistical random effects model only to understand
how to work but I have always the same problem: the 'beta' is not uniquely
specified (I don't know if I have to consider Rest state or not and, if
yes, how).
In the same way I tried using adjMean output files instead of Con_*.img
files for each subject but the problem is still there.
Then...there is someone who can help me and explain, step by step, in a
simple and practical way, what I should do?
Thanks a lot for spending this time.
Eleonora Fornari
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